Ultra low loss and high-density routing between cores

ABSTRACT

Embodiments disclosed herein include a package core. In an embodiment, the package core includes a first layer, where the first layer comprises glass. In an embodiment, a second layer is over the first layer, where the second layer comprises glass. In an embodiment, a third layer is over the second layer, where the third layer comprises glass. In an embodiment, a first trace is between the first layer and the second layer. In an embodiment, a second trace is between the second layer and the third layer.

TECHNICAL FIELD

Embodiments of the present disclosure relate to electronic packages, andmore particularly to electronic packages with low loss routing andinductors for power delivery between glass cores in the packagesubstrate. Packages for the purposes of this disclosure can apply toelectronic package substrates, space or pitch transformationinterposers, and/or motherboard PCBs.

BACKGROUND

The data rates for high-speed serial interfaces (e.g., SerDes, PCIe,224G Ethernet) are expected to continue to scale higher, resulting inthe signals experiencing increased insertion loss when routed on atraditional package with standard buildup thicknesses. One alternativeto increasing dielectric thickness to reduce signaling losses is to voidmetal layers directly above and/or below the signal routing layer inorder to increase the effective dielectric thickness of the transmissionline. This allows for the signal traces with a fixed impedance target todesign to a wider trace width and trace spacings without modifying thepackage construction. This concept sometimes referred to as “skip-layerrouting” enables a larger width and spacing at lower losses while stillmeeting the signals impedance target.

However, this skip-layer routing configuration results in an increase inthe package layer count. A standard strip-line signal routeconfiguration requires three metal layers, one signal layer with groundreference layers above and below. A skip-layer signal routingconfiguration requires two additional “skip” metal layers that sitbetween the signal and the reference grounds, totaling five metallayers. This increase in layer count increases the per unit packagecost, negatively impacts fabrication capacity, reduces yield and canincrease the package form factor. On top of the increased layer countimplications, the metal voiding in the skip layers increasemanufacturing risk due to large copper density variations they createwithin the layers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a plan view illustration of a portion of a core with anadhesion layer surrounding a signal routing region and a power region,in accordance with an embodiment.

FIG. 1B is a plan view illustration of a portion of a core without theadhesion layer that shows the signal routing region and the power regionover a glass layer, in accordance with an embodiment.

FIG. 2A is a cross-sectional illustration of a package core with a powerregion and a signal routing region with the lateral traces disposedbetween a pair of glass layers, in accordance with an embodiment.

FIG. 2B is a cross-sectional illustration of the package core throughthe signal routing region, in accordance with an embodiment.

FIG. 2C is a cross-sectional illustration of a package core with asignal routing region that provides a conductive path between two dieside components, in accordance with an embodiment.

FIG. 3A is a cross-sectional illustration of a package core with asignal routing region and a power region, wherein the traces in thepower region are thicker than the traces in the signal routing region,in accordance with an embodiment.

FIG. 3B is a cross-sectional illustration of the package core throughthe signal routing region, in accordance with an embodiment.

FIG. 3C is a cross-sectional illustration of a package core with a powerregion with a trace or plane that fills cavities in the glass cores, inaccordance with an embodiment.

FIG. 4A is a cross-sectional illustration of an electronic package witha multi-layer glass core with routing layers over the glass core, inaccordance with an embodiment.

FIG. 4B is a cross-sectional illustration of an electronic package witha multi-layer glass core with a plurality of routing layers over theglass core, in accordance with an embodiment.

FIG. 5A is a cross-sectional illustration of a package core withrecesses with cavities formed into the glass layers, in accordance withan embodiment.

FIG. 5B is a cross-sectional illustration of the package core in FIG. 5Aafter conductive planes fill the cavities, in accordance with anembodiment.

FIG. 6A is a plan view illustration of a core with a signal routingregion and a power region, in accordance with an embodiment.

FIG. 6B is a plan view illustration of a portion of the power regionwith a planar inductor, in accordance with an embodiment.

FIG. 6C is a plan view illustration of a portion of the power regionwith a planar inductor with two coils in series, in accordance with anembodiment.

FIG. 6D is a cross-sectional illustration of a multi-layer glass corewith an inductor provided between the glass layers, in accordance withan embodiment.

FIG. 6E is a cross-sectional illustration of a multi-layer glass corewith an inductor surrounded by a magnetic material, in accordance withan embodiment.

FIG. 7A is a perspective view illustration of an inductor with twoplanar inductors that are stacked and electrically connected in series,in accordance with an embodiment.

FIG. 7B is a cross-sectional illustration of a multi-layer glass corewith a two-layer inductor between the glass layers, in accordance withan embodiment.

FIG. 7C is a cross-sectional illustration of a multi-layer glass corewith a two layer inductor that is surrounded by a magnetic material, inaccordance with an embodiment.

FIG. 7D is a cross-sectional illustration of a multi-layer glass corewith a non-planar inductor between the glass layers, in accordance withan embodiment.

FIG. 7E is a cross-sectional illustration of a multi-layer glass corewith a non-planar inductor with a magnetic layer surrounding the vias,in accordance with an embodiment.

FIG. 8A is a cross-sectional illustration of a multi-layer glass corewith a power region and a signal routing region, in accordance with anembodiment.

FIG. 8B is a cross-sectional illustration of the multi-layer glass corethrough the signal routing region, in accordance with an embodiment.

FIG. 8C is a cross-sectional illustration of a multi-layer glass corewith a signal routing region that includes an electrical path betweentwo die side components, in accordance with an embodiment.

FIG. 8D is a cross-sectional illustration of a multi-layer glass corewith a signal routing region that includes a pair of electric paths thatconnect die side components, in accordance with an embodiment.

FIG. 8E is a cross-sectional illustration of a multi-layer glass corewith a power region that includes traces or planes that are thicker thanthe traces in the signal routing region, in accordance with anembodiment.

FIG. 9A is a cross-sectional illustration of a multi-layer glass corewith a series of cavities formed into the glass layers over the traces,in accordance with an embodiment.

FIG. 9B is a cross-sectional illustration of the multi-layer glass corewith conductive planes that fill in the cavities into the glass layers,in accordance with an embodiment.

FIG. 9C is a cross-sectional illustration of a multi-layer glass corewith a series of cavities into the glass layers over the signal routingtraces, in accordance with an embodiment.

FIG. 9D is a cross-sectional illustration of the multi-layer glass corewith conductive planes filling the cavities, in accordance with anembodiment.

FIG. 10A is a cross-sectional illustration of a multi-layer glass corewith a first glass layer, a second glass layer, and a thick adhesivelayer, in accordance with an embodiment.

FIG. 10B is a cross-sectional illustration of a multi-layer glass corewith power traces that are thicker than the signal routing traces, inaccordance with an embodiment.

FIG. 10C is a cross-sectional illustration of the signal routing tracesof the multi-layer glass core, in accordance with an embodiment.

FIG. 10D is a cross-sectional illustration of the signal routing traceswith different routing architectures within a single multi-layer glasscore, in accordance with an embodiment.

FIG. 11A is a cross-sectional illustration of a multi-layer glass corewith cavities in the glass layers over the signal traces, in accordancewith an embodiment.

FIG. 11B is a cross-sectional illustration of the multi-layer glass corewith a conductive plane filling the cavities in the glass layers, inaccordance with an embodiment.

FIG. 12A is a cross-sectional illustration of a multi-layer glass core,in accordance with an embodiment.

FIG. 12B is a cross-sectional illustration of a multi-layer glass corewith adhesive layers between the glass layers, in accordance with anembodiment.

FIG. 13 is a cross-sectional illustration of an electronic system with apackage substrate with a multi-layer glass core, in accordance with anembodiment.

FIG. 14 is a schematic of a computing device built in accordance with anembodiment.

EMBODIMENTS OF THE PRESENT DISCLOSURE

Described herein are electronic devices with low loss routing andinductors for power delivery between glass cores in the packagesubstrate, in accordance with various embodiments. Packages for thepurposes of this disclosure can apply to electronic package substrates,space or pitch transformation interposers, and/or motherboard PCBs. Inthe following description, various aspects of the illustrativeimplementations will be described using terms commonly employed by thoseskilled in the art to convey the substance of their work to othersskilled in the art. However, it will be apparent to those skilled in theart that the present invention may be practiced with only some of thedescribed aspects. For purposes of explanation, specific numbers,materials and configurations are set forth in order to provide athorough understanding of the illustrative implementations. However, itwill be apparent to one skilled in the art that the present inventionmay be practiced without the specific details. In other instances,well-known features are omitted or simplified in order not to obscurethe illustrative implementations.

Various operations will be described as multiple discrete operations, inturn, in a manner that is most helpful in understanding the presentinvention, however, the order of description should not be construed toimply that these operations are necessarily order dependent. Inparticular, these operations need not be performed in the order ofpresentation.

As noted above, high speed serial interfaces (e.g.,serializer/deserializer (SerDes) signals) experience higher insertionloss when the nets are routed on the package with standard buildupthicknesses. However, instead of using skip layers to improve losses,embodiments disclosed herein route the SerDes signals through the core.In a particular embodiment, a multi-layer core is used, and the SerDessignals are routed between core layers. In some embodiments, the corelayers comprise glass or buildup film and glass. Due to the thickness ofthe glass core layers (e.g., 100 µm or more) there is no need for skiplayers, as the glass cores provide lower capacitance allowing for signaltraces to have large trace widths and trace spacings. This enables lowlosses while meeting impedance targets. Without skip layers, the layercount of the package substrate is reduced. Additionally, manufacturingcomplexities due to copper density variation are avoided.

In addition to providing routing for SerDes applications, it is to beappreciated that other types of signal routing may be integrated intothe multi-layer core as well. For example, cavities in the core layersmay be filled with a ground plane in order to reduce the distancebetween the ground and the trace. As such, standard differential routingor single ended high-density routing (which both need ground planescloser to the traces) may be implemented in some embodiments.

In yet another embodiment, it is to be appreciated that power deliveryarchitectures may also be included in the multi-layer core. In someinstances, the thickness of the power delivery traces may be greaterthan the thickness of the signaling traces. This can be implemented byeither forming recesses in the glass core layers, or by increasing thedistance between two glass cores. In yet another embodiment, powerdelivery features may include inductors. For example, spiral inductors(e.g., in a single layer or multiple layers) may be provided betweenglass cores to provide inductance below the die. Some embodiments mayalso include magnetic material around the inductors to improve theperformance of the inductors.

Referring now to FIG. 1A, a plan view illustration of a portion of amulti-layer core 120 is shown, in accordance with an embodiment. Theillustrated view shows the core 120 with a top layer (e.g., a top glasslayer) removed. The resulting image depicts a signal routing region 103that surrounds a power delivery region 104. While shown in FIG. 1A andthe following Figures as being different regions that are adjacent toeach other, it is to be appreciated that the signal routing region 103and the power delivery region 104 may not be as clearly defined asillustrated. For example, there may be some power delivery structuresinside the signal region, especially when there are some die sidecomponents. Similarly, signal traces and power planes may coexist in thepower delivery region 104, especially in regions near the die edge andwhere the IP blocks are located. That is to say, power deliverycomponents and signaling components may both be located within a givenregion of the device. An interface material 122 may also be provided inthe layer between glass layers. The interface material 122 may be anadhesive layer. The interface material 122 may adhere to the conductivefeatures and the glass layers. In a particular embodiment, the interfacematerial 122 may be a buildup film or the like.

In FIG. 1A, the signal routing region 103 and the power delivery region104 are shown as uniform blocks. That is, the structure of individualtraces and/or other conductive features in the signal routing region 103and the power delivery region 104 are omitted for simplicity. Thoseskilled in the art will recognize that traces and the like may populatethe regions 103 and 104, as will be described in greater detail below.Additionally, it is to be appreciated that the interface material 122may surround the individual traces and other conductive features withinthe regions 103 and 104.

Referring now to FIG. 1B, a plan view illustration of the multi-layercore 120 is shown in accordance with an additional embodiment. Thedifference between FIGS. 1B and 1A is that in FIG. 1B the interfacematerial 122 is omitted. As such, the underlying core layer 110 isvisible. In an embodiment, the core layer 110 may be a glass core layer,which sometimes may be referred to as a glass layer 110 for short. In anembodiment, the glass layer 110 may be any type of glass suitable forelectronic packaging architectures. In some embodiments, a thickness ofthe glass layer 110 may be approximately 100 µm or greater. Though it isto be appreciated that thinner glass layers 110 may also be used in someembodiments.

Referring now to FIG. 2A, a cross-sectional illustration of amulti-layer core 220 is shown, in accordance with an embodiment. In FIG.2A, it is to be appreciated that only the multi-layer core 220 is shownfor simplicity. It is to be appreciated that additional routing can beprovided above and/or below the multi-layer core 220 in standard builduplayers. In an embodiment, the multi-layer core 220 comprises a firstglass layer 210 _(A) and a second glass layer 210 _(B). An interfacelayer 222 may be provided between the glass layers 210 _(A) and 210_(B). The interface layer 222 may be an adhesive layer that bonds thefirst glass layer 210 _(A) to the second glass layer 210 _(B). In anembodiment, the interface layer 222 may have a thickness that issubstantially equal to a thickness of the traces 241 and 231 providedbetween the glass layers 210. As used herein, substantially equal mayrefer to two values that are within 10% of each other. For example, 9 µmmay be substantially equal to 10 µm in some embodiments. In a particularembodiment the thicknesses of the traces 241 and 231 may beapproximately 30 µm or less or approximately 15 µm or less.

In an embodiment, the multi-layer core 220 may comprise a signal routingregion 203 and a power delivery region 204. In an embodiment, trace 241may be provided in the signal routing region 203. The trace 241 may becoupled to the top and bottom of the core 220 by vias 242. In aparticular embodiment, the trace 241 may be a SerDes signal trace.Though, it is to be appreciated that other signal routing architecturesmay also be included in the signal routing region 203. That is, low losssignals may be able to provide communicative coupling between the frontand backside of the multi-layer core 220. In an embodiment, trace 231may be provided in the power delivery region 204. While referred to as atrace 231, it is to be appreciated that the trace 231 may also be aplane in some embodiments. The trace 231 may be coupled to the top andbottom surface of the core 220 by vias 232. In an embodiment, groundplanes 211 may be provided above and/or below the core 220. Ground vias212 may pass through the glass layers 210 _(A) and 210 _(B) and throughthe interface layer 222.

Referring now to FIG. 2B, a cross-sectional illustration of themulti-layer core 220 in FIG. 2A along line B-B′ is shown, in accordancewith an embodiment. In an embodiment, the cross-section is through thesignal routing region 203. In an embodiment, traces 241 may extend intoand out of the plane of FIG. 2B. Sidewalls of the traces 241 may becontacted by the interface layer 222. The top and bottom surfaces of thetraces 241 may be contacted by the glass layers 210 _(A) and 210 _(B).

In an embodiment, the traces 241 may be arranged in pairs (e.g., toprovide differential signaling). Each of the signaling pairs may besurrounded by ground planes 211 and ground vias 212. The distancebetween the ground planes 211 and the traces 241 may be set by thethicknesses of the glass layers 210 _(A) and 210 _(B). For example, thedistance between the ground planes 211 and the traces 241 may beapproximately 100 µm or greater. As such, ultra-low loss signalingtraces can be provided in some embodiments. Particularly, the wide gapbetween the ground planes 211 and the traces 241 may allow for widertrace 241 widths and trace 241 spacings.

Referring now to FIG. 2C, a cross-sectional illustration of amulti-layer core 220 is shown, in accordance with an additionalembodiment. In an embodiment, the multi-layer core 220 may be similar tothe multi-layer core 220 in FIG. 2A with the exception of the routingpath in the signal routing region. Instead of providing a signal pathfrom the top surface of the core 220 to a bottom surface of the core 220(as is the case in FIG. 2A), the signal path provides routing betweentwo locations on the top surface of the core 220. Such an embodiment maybe useful when a signal is routed from a die to another die sidecomponent. That is, low loss signals may be able to providecommunicative coupling between components on a single side of thepackage substrate. For example, the additional die side component mayinclude a connector, an optical module, a die, a chiplet, or the like.

Referring now to FIG. 3A, a cross-sectional illustration of amulti-layer core 320 is shown, in accordance with another embodiment. Inan embodiment, the core 320 may comprise a first glass layer 310 _(A)and a second glass layer 310 _(B). An interface layer 322 may beprovided between the glass layers 310 _(A) and 310 _(B). In anembodiment, the interface layer 322 is thicker than the embodimentsdescribed in greater detail above. Due to the increase in thickness, thepower delivery trace 331 may be increased in thickness. Increasing thethickness of the power delivery trace 331 may allow for lower resistanceand improved power delivery performance. In an embodiment, the powerdelivery trace 331 may be coupled to the top and bottom surface of thecore 320 by vias 332. Additionally, it is to be appreciated that thepower delivery trace 331 may be a plane in some embodiments.

In an embodiment, the signal routing trace 341 may include vias 342 thatconnect the signal routing trace 341 to the top and bottom of the core320. Additionally, it is to be appreciated that a thickness of thesignal routing trace 341 may be smaller than the thickness of the powerdelivery trace 331. When the signal routing trace 341 is thinner thanthe interface layer 322, portions of the interface layer 322 may beprovided over a top surface of the signal routing trace 341.Alternatively, the signal routing trace 341 may be contacting the glasslayer 310 _(B), and a portion of the interface layer 322 may be betweena bottom surface of the signal routing trace 341 and the glass layer 310_(A).

The core 320 may also comprise ground planes 311 and ground vias 312.Similar to embodiments described above, the glass layers 310 _(A) and310 _(B) provide relatively large separations between the ground planes311 and the signal routing trace 341 in order to enable low lossarchitectures.

Referring now to FIG. 3B, a cross-sectional illustration of themulti-layer core 320 in FIG. 3A along line B-B′ is shown, in accordancewith an embodiment. In an embodiment, the cross-section is through thesignal routing region. In an embodiment, signal routing traces 341 mayextend into and out of the plane of FIG. 3B. Sidewalls of the signalrouting traces 341 may be contacted by the interface layer 322.Additionally, the top surface of the signal routing traces 341 may becontacted by the interface layer 322. The bottom surface of the signalrouting traces 341 may be in contact with the bottom glass layer 310_(A).

In an embodiment, the signal routing traces 341 may be arranged in pairs(e.g., to provide differential signaling). Each of the signaling pairsmay be surrounded by ground planes 311 and ground vias 312. The distancebetween the ground planes 311 and the signal routing traces 341 may beset by the thicknesses of the glass layers 310 _(A) and 310 _(B) and athickness of the interface layer 322. For example, the distance betweenthe ground planes 311 and the signal routing traces 341 may beapproximately 100 µm or greater. As such, ultra-low loss signalingtraces can be provided in some embodiments. Particularly, the wide gapbetween the ground planes 311 and the signal routing traces 341 mayallow for wider signal routing trace 341 widths and signal routing trace341 spacings.

Referring now to FIG. 3C, a cross-sectional illustration of amulti-layer core 320 is shown, in accordance with yet anotherembodiment. As shown, the signal routing trace 341 couples together vias342 that reach to the top surface of the core 320. In other embodiments,the vias 342 may provide routing between the top surface and the bottomsurface of the core 320, similar to the embodiment shown in FIG. 3A.

FIG. 3C differs from the embodiment shown in FIG. 3A, in that theinterface layer 322 is reduced in thickness. For example, the thicknessof the interface layer 322 may be substantially equal to the thicknessof the signal routing trace 341. However, the power delivery trace 331may still have a thickness that is greater than the signal routing trace341. The extra thickness of the power delivery trace 331 may beaccommodated by cavities 315 into the glass layers 310 _(A) and 310_(B). As illustrated, portions of the sidewalls of the power deliverytrace 331 may be in direct contact with the glass layers 310 _(A) and310 _(B) in addition to contacting the interface layer 322. In theillustrated embodiment, cavities 315 are provided above and below thepower delivery trace 331. However, in other embodiments, a cavity 315may be provided only above or below the power delivery trace 331.Furthermore, while referred to as a power delivery trace 331, it is tobe appreciated that power delivery trace 331 may optionally be a plane.The cavities 315 may be blind cavities 315. That is, the cavities 315 donot pass entirely through a thickness of the glass layers 310 _(A) and310 _(B). Unless stated otherwise, cavities disclosed herein are blindcavities. In an embodiment, the blind cavities may be filled with metal.In certain instances, the blind cavities are formed in the glass layer.

Referring now to FIG. 4A, a cross-sectional illustration of anelectronic package 400 is shown, in accordance with an embodiment. Inthe illustrated embodiment, the buildup layers are only shown above thetop surface of the core for simplicity. However, it is to be appreciatedthat similar buildup layers would be present on the bottom side of thecore as well. The bottom side of the core may have more or fewer builduplayers than on the top side, and/or there may not be any routing on thebottom side of the core. Additionally, it is to be appreciated that morebuildup layers can be provided over the top surface of the core. Sinceno skip layers are needed, each of the traces 451 may be spaced awayfrom the ground planes 411 by a single buildup layer 408 similar tostandard stripline routing.

In an embodiment, the electronic package 400 in FIG. 4A illustrates thereduction in layer count possible by using embodiments disclosed herein.For example, the low loss layer is provided within the core instead ofin the buildup layers. If the low loss layers were provided in thebuildup layers, skip layer routing would be necessary. This wouldrequire an additional three routing layers. That is, four additionallayers would be added above the core, and the traces 441 would beeliminated, leaving a total of three extra routing layers. Instead, abottom glass layer 410 _(A) and a top glass layer 410 _(B) provide theneeded distance between the traces 441 and the ground planes 411. Aninterface layer 422 may secure the top glass layer 410 _(B) to thebottom glass layer 410 _(A). In this manner, a two routing layerembodiment can be implemented with seven layers (including the top andbottom layers).

In a case where additional routing layers are needed, additional builduplayers 408 and standard routing can be added. For example, in FIG. 4Bthree routing layers are shown. Two standard routing layers with traces451 are provided in the buildup layers 408. Ultra-low loss traces 441are provided between the top glass layer 410 _(B) and the bottom glasslayer 410 _(A). In such an embodiment, the entire electronic package canbe implemented in eleven layers. Without the use of embodiments shownhere, a similar electronic package would require fourteen layers.Additionally, if two standard loss routing layers and one ultra-low losslayer is needed, then embodiments disclosed herein would still only needeleven layers, while conventional packaging would require eighteenlayers. As such, the number of layers is lower and the cost andcomplexity of fabricating the electronic package is reduced.

Referring now to FIG. 5A, a cross-sectional illustration of amulti-layer core 520 is shown, in accordance with an additionalembodiment. In addition to providing routing for ultra-low loss signals,embodiments may include incorporating other routing architectures intothe multi-layer core 520. For example, standard differential routing andsingle ended high-density routing may also be included in themulti-layer core 520. In order to accommodate the different routingarchitectures, the ground planes may be moved closer to the traces. Forexample, the ground planes may be brought closer to the traces byincorporating cavities into the glass layers 510 when the cavities arefilled with metal.

As shown in FIG. 5A, a first glass layer 510 _(A) and a second glasslayer 510 _(B) may be bonded to each other by an interface layer 522.Traces 541 and 544 may be provided between the glass layers 510 _(A) and510 _(B). In an embodiment, the leftmost set of traces 543 may be forthe standard differential routing, the center pair of traces 541 may befor the ultra-low loss routing, and the right set of traces 544 may befor the single ended high-density routing. While the trace width andspacing between traces 541 and 543 look similar, it is to be appreciatedthat in some instances, the ultra-low loss traces 541 may have largertrace widths and spacings than the standard differential routing traces543. The standard differential routing may be provided between cavities552 that are formed into the glass layers 510 _(A) and 510 _(B). Thesingle ended high-density routing traces 544 may be provided betweencavities 553 in the glass layers 510 _(A) and 510 _(B). The cavities 553may be deeper than the cavities 552. As such, the ground plane will becloser to the single ended high-density routing traces 544 than theultra-low loss traces 541.

Referring now to FIG. 5B, a cross-sectional illustration of themulti-layer core 520 after the ground planes 511 and ground vias 512 areformed is shown, in accordance with an embodiment. As shown, conductiveblocks 554 fill the cavities 552, and conductive blocks 555 fill thecavities 553. The conductive blocks 554 and 555 may be connected to eachother by the ground planes 511. As such, the conductive blocks 554 and555 are also held at the ground potential. The conductive blocks 554 and555 reduce the distance between the traces 543 and 544 and the nearestground reference. As shown, the ultra-low loss traces 541 in the middlemay be separated from the ground planes 511 by a first thickness T₁. Inthe illustrated embodiment, the thickness between the top of theultra-low loss traces 541 and the ground planes 511 is alsosubstantially equal to the first thickness T₁. However, it is to beappreciated that the thickness between the top of ultra-low loss traces541 and the ground plane 511 may be equal to, less than, or greater thanthe first thickness T₁. The differential routing traces 543 may beseparated from the ground planes 511 by a second thickness T₂ that issmaller than the first thickness T₁. Furthermore, it is to beappreciated that the thickness between the top of traces 543 and theground plane 511 may be equal to, less than, or greater than the secondthickness T₂. Additionally, the single ended high-density routing traces544 may be separated from the ground planes 511 by a third thickness T₃that is smaller than the second thickness T₂. In the illustratedembodiment, the thickness between the top of the single endedhigh-density routing traces 544 and the ground planes 511 is alsosubstantially equal to the third thickness T₃. However, it is to beappreciated that the thickness between the top of single endedhigh-density routing traces 544 and the ground planes 511 may be equalto, less than, or greater than the third thickness T₃. As such, aplurality of different routing architectures may be provided within asingle multi-layer core, in accordance with various embodimentsdisclosed herein.

Referring now to FIGS. 6A-7C, illustrations depicting architectures usedin the power delivery region are shown, in accordance with variousembodiments. As shown in the following Figures, inductor architecturesmay be included within a multi-layer core. In one embodiment, theinductors are planar spirals. In yet another embodiment, a pair ofplanar inductors are stacked over each other to provide more inductance.In some embodiments, magnetic materials may be provided around theinductors.

Referring now to FIG. 6A, a plan view illustration of a multi-layer core620 is shown, in accordance with an embodiment. In an embodiment, themulti-layer core 620 illustrates a middle layer where the routing islocated. A signal routing region 603 may surround a power region 604.The power region 604 may be located below a die (not shown). In theillustrated embodiment, an interface layer 622 may surround the signalrouting region 603 and the power region 604. While shown as solidblocks, it is to be appreciated that the power region 604 and the signalrouting region 603 may comprise a plurality of traces and otherstructures. Interface material from the interface layer 622 may directlycontact the traces and structures within the signal routing region 603and the power region 604.

In an embodiment, the power region 604 may comprise a plurality ofinductor blocks 606. The inductor blocks 606 may each comprise a planarinductor that is formed between the glass layers of the multi-layercore. The inductors may include planar inductors with any suitablearchitecture. For example, in FIG. 6B, a zoomed in illustration of oneof the inductor blocks 606 is shown, in accordance with an embodiment.As shown, the inductor block 606 may include a spiral inductor 661. Thespiral inductor 661 may have any number of loops to provide a desiredlevel of inductance.

Referring now to FIG. 6C, a plan view illustration of an inductor block606 is shown, in accordance with an additional embodiment. As shown, theinductor block 606 may include a plurality of spiral inductors 661. Forexample, a first spiral inductor 661 _(A) may be coupled to a secondspiral inductor 661 _(B). The two spiral inductors 661 _(A) and 661 _(B)may be connected to each other in series electrically. While twoinductors 661 are shown, it is to be appreciated that any number ofinductors 661 may be connected to each other in order to provide adesired inductance. In an embodiment, the inductors 661 may be over anunderlying glass layer and surrounded by the interface layer 622.

Referring now to FIG. 6D, a cross-sectional illustration of themulti-layer core 620 is shown, in accordance with an embodiment. Asshown, a pair of glass layers 610 _(A) and 610 _(B) may be bondedtogether by an interface layer 622. Ground planes 611 may be provided ona top surface and a bottom surface of the core 620, and ground vias 612may pass through the glass layers 610 _(A) and 610 _(B). In anembodiment, an inductor 661 may be provided between the glass layers 610_(A) and 610 _(B). The interface layer 622 may also surround theinductor 661. The inductor 661 may be a planar spiral inductor. Forexample, the inductor 661 may be similar to the inductors 661 describedin greater detail above with respect to FIGS. 6B and 6C. The inductor661 may be coupled to the top surface of the core 620 and the bottomsurface of the core 620 by vias 642. In other embodiments, the inductor661 may be coupled to the top side of the core 620 by a pair of vias 642that both pass through the glass layer 610 _(B).

Referring now to FIG. 6E, a cross-sectional illustration of amulti-layer core 620 is shown, in accordance with an additionalembodiment. The core 620 may be substantially similar to the core 620described above with respect to FIG. 6D, with the exception of amagnetic layer 662 being added. Adding magnetic material around theinductor 661 increases the performance of the inductor and helps reducenoise from the inductor 661. As such, smaller inductor 661 footprintsand/or fewer inductors 661 may be needed for a given architecture.

In an embodiment, the magnetic layer 662 may be provided above and belowthe inductor 661. The magnetic layer 662 may extend into the top glasslayer 610 _(B) and into the bottom glass layer 610 _(A). In otherembodiments, the interface layer 622 may be thicker than the inductor661, and the magnetic layers 662 may be entirely within the interfacelayer 622. In an embodiment, a magnetic layer 662 may be provided overonly a top surface of the inductor 661 or only under a bottom surface ofthe inductor 661.

Referring now to FIG. 7A, a perspective view illustration of amulti-layer inductor 706 is shown, in accordance with an embodiment. Theinductor 706 shown in FIG. 7A is illustrated without the surroundingmaterials, such as the glass layers and the interface layer. However, itis to be appreciated that the inductor 706 may be provided between theglass layers and surrounded by the interface layer. For example, a firstinductor 761 _(A) may be provided in contact with a bottom glass layer,and a second inductor 761 _(B) may be provided in contact with a topglass layer. Vias 742 may pass through the glass layers, and the via 763may connect the first inductor 761 _(A) to the second inductor 761 _(B).In the illustrated embodiment, the first inductor 761 _(A) and thesecond inductor 761 _(B) are connected in series electrically. Howeverin other embodiments, the first inductor 761 _(A) and the secondinductor 761 _(B) may be connected in parallel electrically.

Referring now to FIG. 7B, a cross-sectional illustration of amulti-layer core 720 is shown, in accordance with an embodiment. Asshown, the core 720 comprises a first glass layer 710 _(A) and a secondglass layer 710 _(B). Ground planes 711 may be provided over the top andbottom surfaces of the core 720, and ground vias 712 may pass throughthe thickness of the core 720. In an embodiment, an interface layer 722is provided between the first glass layer 710 _(A) and the second glasslayer 710 _(B). The interface layer 722 may have a thickness that isgreater than the thickness of individual inductors 761. For example, afirst inductor 761 _(A) may be provided over the first glass layer 710_(A), and a second inductor 761 _(B) may be provided under the secondglass layer 710 _(B). A portion of the interface layer 722 may separatethe first inductor 761 _(A) from the second inductor 761 _(B).

In an embodiment, the first inductor 761 _(A) may be coupled to a bottomof the core 720 by a via 742, and the second inductor 761 _(B) may becoupled to a top of the core 720 by a via 742. The first inductor 761_(A) may be coupled to the second inductor 761 _(B) by a via 763 thatpasses through the interface layer 722. In such an architecture, theinterface layer 722 may surround portions of the inductors 761 _(A) and761 _(B), and make direct contact with the inductors 761 _(A) and 761_(B).

Referring now to FIG. 7C, a cross-sectional illustration of a core 720is shown, in accordance with yet another embodiment. In an embodiment,the core 720 in FIG. 7C may be substantially similar to the core 720 inFIG. 7B, with the exception of the inclusion of magnetic layers 762. Inan embodiment, the magnetic layers 762 may surround the inductors 761_(A) and 761 _(B). As such, the inductors 761 _(A) and 761 _(B) may beseparated from the interface layer 722 in some embodiments. In anembodiment, the magnetic layers 762 may be separated from each otherwith a portion of the interface layer 722 between the top magneticlayers 762 and the bottom magnetic layers 762. In other embodiments, asingle block of magnetic material may surround both the first inductor761 _(A) and the second inductor 761 _(B).

As illustrated, the magnetic material 762 may extend into the glasslayers 710 _(A) and 710 _(B). For example, cavities may be formed intothe glass layers 710 in order to accommodate the magnetic material 762.In other embodiments, the magnetic material 762 may only be providedwithin a thickness of the interface layer 722. In such embodiments, thetop surface of the inductor 761 _(B) may directly contact the glasslayer 710 _(B), and the bottom surface of the inductor 761 _(A) maydirectly contact the glass layer 710 _(A). Similar to some embodimentsabove, the inductors 761 _(A) and 761 _(B) may be made thicker byproviding cavities in the glass and filling them with the metal.Additionally, it is to be appreciated that additional inductors 761 maybe provided in the Z-direction if there are additional glass core layersprovided. Such an embodiment may increase inductance without having tooccupy additional in-plane real estate.

While planar inductors are shown in FIGS. 7A-7C, it is to be appreciatedthat embodiments may also include non-planar or vertically orientedinductors. Examples of such embodiments are shown in FIGS. 7D and 7E.

Referring now to FIG. 7D, a cross-sectional illustration of a core 720is shown, in accordance with an embodiment. The core 720 may comprise afirst glass layer 710 _(A) that is coupled to a second glass layer 710_(B) by an interface layer 722. In an embodiment, vias 742 couple thetop side of the core to an inductor. In an embodiment, the inductor is avertically oriented (non-planar) inductor. The inductor comprises two ormore vertical vias 758 that are coupled together by lateral traces 759.In the illustrated embodiment, both ends of the inductor are coupled tothe top surface of the core 720. However, it is to be appreciated thatone of the ends of the inductor may be coupled to a backside of the core720.

Referring now to FIG. 7E, a cross-sectional illustration of a core 720is shown, in accordance with an additional embodiment. In an embodiment,the core 720 in FIG. 7E may be substantially similar to the core 720 inFIG. 7D, with the exception of there being magnetic material 762surrounding the inductor. In the illustrated embodiment, magneticmaterial 762 may surround the traces 759 and the vias 758. However,embodiments may also include the magnetic material 762 only around thetraces 759 or only around the vias 758.

In FIGS. 7D and 7E, the traces 759 are shown as being entirely withinthe interface layer 722. However, it is to be appreciated that thetraces 759 may be partially or entirely within the first glass layer 710_(A) and/or the second glass layer 710 _(B). Additionally, the interfacelayer 722 may be an adhesive or another glass layer.

Referring now to FIGS. 8A-8E, a series of cross-sectional illustrationsdepicting multi-layer cores 820 are shown, in accordance with additionalembodiments. Instead of being limited to a pair of glass layers 810, thecores 820 may have a plurality of glass layers 810. For example, theremay be three glass layers 810 _(A), 810 _(B), and 810 _(C). The additionof a third glass layer 810 may allow for an additional routing layer tobe provided within the cores 820.

Referring now to FIG. 8A, a cross-sectional illustration of amulti-layer core 820 is shown, in accordance with an embodiment. In anembodiment, the core 820 may comprise a first glass layer 810 _(A), asecond glass layer 810 _(B), and a third glass layer 810 _(C). The glasslayers 810 may be adhered to each other by interface layers 822. Forexample, a first interface layer 822 _(A) couples the first glass layer810 _(A) to the second glass layer 810 _(B), and a second interfacelayer 822 _(B) couples the second glass layer 810 _(B) to the thirdglass layer 810 _(C). The glass layers 810 may be any suitable glassmaterial. In an embodiment, a thickness of the glass layers 810 may beapproximately 100 µm or greater. In an embodiment, the interface layers822 may be a buildup film or any other dielectric material that hasadhesive properties.

In an embodiment, the core 820 may comprise a signal routing region 803and a power delivery region 804. In the signal routing region 803, lowloss signal routing may be provided along traces 841. In an embodiment,the traces 841 may be provided in the interface layers 822. For example,a first trace 841 is provided in the first interface layer 822 _(A), anda second trace 841 is provided in the second interface layer 822 _(B).The top and bottom surfaces of the traces 841 may contact glass layers810, and the sidewall surfaces of the traces 841 may contact thematerial of the interface layers 822. In an embodiment, vias 842 mayprovide connections between the traces 841 and the top and bottom of thecore 820.

In an embodiment, power delivery traces 831 may be provided in the powerdelivery region 804. The power delivery traces 831 may also be providedin the interface layers 822 _(A) and 822 _(B). Vias 832 may connect thepower delivery traces 831 to the top and bottom surfaces of the core820. In an embodiment, the power delivery traces 831 may havethicknesses that are substantially equal to the thickness of the signalrouting traces 841.

In an embodiment, ground planes 811 may be provided above and below thecore 820. Ground vias 812 may pass through a thickness of the core 820.For example, ground vias 812 may pass through glass layers 810 and theinterface layers 822. Due to the thickness of the glass layers 810, theground planes 811 are separated from the traces 841 a distance suitablefor low loss operation. For example, traces 841 may be consideredultra-low loss signaling traces 841. In some embodiments, the traces 841may be SerDes signaling traces.

Referring now to FIG. 8B, a cross-sectional illustration of the core 820through the signal routing region 803 is shown, in accordance with anembodiment. In the illustrated view, the signal traces 841 extend intoand out of the plane of FIG. 8B. Each of the traces 841 may be providedin the interface layers 822 _(A) or 822 _(B). As shown, each of thetraces 841 are separated from a ground plane 811 by the thickness of theglass layers 810 _(A), 810 _(B), and 810 _(C). In some embodiments, theglass layers 810 may be approximately 100 µm thick or greater. As such,there is a low capacitance between the traces 841 and the ground planes811. This allows for ultra-low loss operation of the traces 841. Asillustrated, the top and bottom surfaces of the traces 841 may be indirect contact with the glass layers 810. Sidewalls of the traces 841may be in direct contact with the interface layers 822 _(A) or 822 _(B).That is, the thickness of the traces 841 may be substantially equal to athickness of the interface layers 822.

Referring now to FIG. 8C, a cross-sectional illustration of amulti-layer core 820 is shown, in accordance with an additionalembodiment. The core 820 in FIG. 8C may be substantially similar to thecore 820 in FIG. 8A, with the exception of the routing in the signalrouting region. In FIG. 8A, the traces 841 are both connected to the topand bottom surfaces of the core 820. In contrast, in FIG. 8C, a firsttrace 841 is coupled to the top and bottom surfaces of the core 820, anda second trace 841 is coupled between two locations on the top surfaceof the core 820.

Such an embodiment may be beneficial when a die (not shown) needs to becoupled to an additional die side component. For example, the die sidecomponent may include, but is not limited to, a connector, an opticalmodule, another die or chiplet, or the like. In the illustratedembodiment, the first trace 841 is provided in the first interface layer822 _(A) and the second trace 841 is provided in the second interfacelayer 822 _(B). However, it is to be appreciated that the two traces 841may be implemented in the same interface layer 822 in some embodiments.Additionally, it is to be appreciated that the first trace 841 thatconnects the top of the multi-layer core 820 to the bottom of themulti-layer core 820 can be implemented in the second interface layer822 _(B), and/or the second trace 841 connecting two locations on thetop side of the multi-layer core 820 may be implemented in the firstinterface layer 822 _(A).

Referring now to FIG. 8D, a cross-sectional illustration of amulti-layer core 820 is shown, in accordance with yet anotherembodiment. The core 820 in FIG. 8D may be substantially similar to thecore 820 in FIG. 8C, with the exception of the routing of the trace 841in the first interface layer 822 _(A). Instead of being connected to thetop surface and the bottom surface of the core 820, the trace 841 iscoupled between two locations on the top surface of the core 820. Forexample, vias 842 at each end of the trace 841 extend from the trace 841to the top surface of the core 820. Such an embodiment may allow for adie to connect to another die side component, such as a connector, anoptical module, or the like.

Referring now to FIG. 8E, a cross-sectional illustration of amulti-layer core 820 is shown, in accordance with another embodiment.The core 820 in FIG. 8E may be substantially similar to the core 820 inFIG. 8D, with the exception of the architecture of the power deliverytraces 831 in the power delivery region. Instead of having a thicknessthat is substantially equal to the thicknesses of the traces 841, thepower delivery traces 831 have thicknesses that are greater than thethicknesses of the traces 841. Increasing the thickness of the powerdelivery traces 831 reduces resistance along the path and improves powerdelivery performance. Furthermore, it is to be appreciated that thepower delivery traces 831 may also be planes in some embodiments.

In order to accommodate the larger thickness of the traces 831, cavities833 may be formed into the glass layers 810 and filled with metal. Inthe illustrated embodiment, cavities 833 are formed into the top surfaceof the first glass layer 810 _(A), top and bottom surfaces of the secondglass layer 810 _(B), and the bottom surface of the third glass layer810 _(C). In other embodiments, the cavities 833 may be formed in onlythe first glass layer 810 _(A) and the third glass layer 810 _(C).Generally, a cavity 833 may be formed in one or more of the top surfaceof the first glass layer 810 _(A), the bottom surface of the secondglass layer 810 _(B), the top surface of the second glass layer 810_(B), and the bottom surface of the third glass layer 810 _(C).

Referring now to FIGS. 9A-9D, a series of cross-sectional illustrationsof multi-layer cores 920 are shown, in accordance with additionalembodiments. As shown, cavities may be formed into the glass layers 910in order to modulate the distance between traces 941 and the groundplanes 911. As such, different types of signaling architectures may beprovided in the multi-layer cores 920 in addition to the ultra-low losssignaling traces (e.g., for use with SerDes signaling).

Referring now to FIG. 9A, a cross-sectional illustration of amulti-layer core 920 is shown, in accordance with an embodiment. In anembodiment, the core 920 comprises a first glass layer 910 _(A), asecond glass layer 910 _(B), and a third glass layer 910 _(C). In anembodiment, the glass layers 910 are secured together by interfacelayers 922. In an embodiment, traces 941 may be provided in theinterface layers 922. That is, the top and bottom surface of the traces941 may contact the glass layers 910 and the sidewalls of the traces 941may contact the interface layers 922. In an embodiment, the traces 941may be paired together in order to enable dual stripline routing.However, dual stripline routing does not need a large distance betweenthe traces 941 and the ground plane.

Accordingly, cavities 965 may be formed into the glass layers 910. Thecavities 965 may be blind cavities 965. That is, the cavities 965 do notpass entirely through a thickness of the glass layer 910. In anembodiment, the cavities 965 are formed into the first glass layer 910_(A) and the third glass layer 910 _(C). That is, in some embodiments,the second glass layer 910 _(B) is left unaltered, with no cavities 965.In the illustrated embodiment, each of the cavities 965 are shown asbeing substantially the same depth. However, it is to be appreciatedthat the depth of the various cavities 965 may be varied. It is to beappreciated that the metal between the third glass layer 910 _(C) andinterface layer 922, between the second glass layer 910 _(B) and theinterface layers 922, between the first glass layer 910 _(A) and theinterface layer 922, and vias through the interface layers 1122 areomitted in order to simplify the Figure.

Referring now to FIG. 9B, a cross-sectional illustration of the core 920after conductive material is plated over the glass layers 910 is shown,in accordance with an embodiment. It is to be appreciated thatmetallization for the different layers will occur at differentmanufacturing operations, and FIG. 9B shows the completion of the corelayers. In an embodiment, the conductive material may form ground planes911. Conductive blocks 966 may also be provided in the location of thecavities 965. The conductive blocks 966 may be connected to each otherby the ground planes 911. As such, the conductive blocks 966 are alsoheld at the ground potential. The conductive blocks 966 reduce thedistance between the traces 941 and the nearest ground reference. Such aconfiguration may be suitable for dual stripline routing. In someembodiments, ground vias 912 may also be provided through thicknesses ofthe glass layers 910.

Referring now to FIG. 9C, a cross-sectional illustration of amulti-layer core 920 is shown, in accordance with yet anotherembodiment. In an embodiment, the core 920 may comprise a first glasslayer 910 _(A), a second glass layer 910 _(B), and a third glass layer910 _(C). Conductive traces 941 and 944 may be provided in interfacelayers 922 between the glass layers 910. Instead of providing a singletype of signal routing architectures, embodiments allow for a pluralityof different signal routing architectures. The difference in the routingtypes can be made by providing cavities 967 and 968 of different depthsinto the glass layers 910. As such, the distance to the ground plane canbe modulated for each routing architecture.

In an embodiment, the pair of traces 941 on the far left side of thecore 920 are suitable for ultra-low loss signaling (e.g., SerDessignaling). The low loss characteristic is provided because the distanceto the ground planes will be the entire thickness of the second glasslayer 910 _(B) and the third glass layer 910 _(C). The middle pair oftraces 943 are suitable for high-density high-speed differentialsignaling. The cavities 967 in the first glass layer 910 _(A) and thesecond glass layer 910 _(B) reduce the distance between the traces 943and the ground plane. On the far right, a set of traces 944 are suitablefor high-density single ended signal routing. In such an embodiment,cavities 968 in the second glass layer 910 _(B) and the third glasslayer 910 _(C) reduce the distance between the traces 944 and the groundplane. It is to be appreciated that the positioning of the traces 941and 944 is provided as an example. That is, the traces 941 and 944 arenot limited to the layers shown, nor is the sequential ordering of thetraces 941 and 944 from left to right to be construed as limitingembodiments disclosed herein. It is to be appreciated that the metalbetween the third glass layer 910 _(C) and interface layer 922, betweenthe second glass layer 910 _(B) and the interface layers 922, betweenthe first glass layer 910 _(A) and the interface layer 922, and viasthrough the interface layers 1122 are omitted in order to simplify theFigure.

Referring now to FIG. 9D, a cross-sectional illustration of the core 920after the ground planes 911 are formed is shown, in accordance with anembodiment. As shown, conductive blocks 966 fill the cavities 967 and968. The conductive blocks 966 may be held at ground potential by theground planes 911 and the ground vias 912. Furthermore, each of thesignaling architectures has a different distance to the ground. Forexample, traces 941 on the left are a distance T₁ from the ground plane911, traces 943 in the middle are a distance T₂ from the groundplane/conductive blocks 911/966, and the traces 944 on the right are adistance T₃ from the ground plane/conductive blocks 911/966. In anembodiment, the distance T₁ is greater than the distance T₂, and thedistance T₂ is greater than the distance T₃. The particular distancesT₁-T₃ can be modulated by changing the thickness of the glass layers 910and/or changing the depths of the cavities 967 and 968. In FIG. 9D, thedistance to ground above and below the traces 941 and 944 are shown asbeing uniform. However, it is to be appreciated that the distance toground above the traces 941 and 944 may be greater than, less than, orequal to the distance to ground below the traces 941 and 944.Additionally such a concept also applies for the ultra low-lossarchitecture if 910 _(C) and 910 _(B) are different thicknesses.

Referring now to FIGS. 10A-10D, a series of illustrations depicting amulti-layer core 1020 is shown, in accordance with additionalembodiments. The core 1020 differ from those described above in thatonly two glass layers 1010 _(A) and 1010 _(B) are provided, and theinterface layer 1022 is thicker. The thicker interface layer 1022provides enough room to have a pair of routing layers. A first routinglayer may be at the bottom of the interface layer 1022 on the firstglass layer 1010 _(A), and a second routing layer may be at the top ofthe interface layer 1022 on the second glass layer 1010 _(B).

Referring now to FIG. 10A, a cross-sectional illustration of amulti-layer core 1020 is shown, in accordance with an embodiment. In anembodiment, the core 1020 comprises a first glass layer 1010 _(A) and asecond glass layer 1010 _(B). In an embodiment, the first glass layer1010 _(A) is coupled to the second glass layer 1010 _(B) by an interfacelayer 1022. In an embodiment, the interface layer 1022 may be anadhesive. While relatively thick (e.g., 20 µm-35 µm) the interface layer1022 may be thinner than that of the glass layers 1010 _(A) and 1010_(B) which may be 100 µm thick or more. In an embodiment, power traces1031 and signaling traces 1041 are provided in the interface layer 1022.For example, a first power trace 1031 _(A) and a first signal trace 1041_(A) may be provided at the bottom of the interface layer 1022, and asecond power trace 1031 _(B) and a second signal trace 1041 _(B) may beprovided at the top of the interface layer 1022. In an embodiment,ground planes 1011 may be provided above and below the core 1020.Additionally, ground vias 1012 may pass through the thicknesses of theglass layers 1010 _(A) and 1010 _(B) and the interface layer 1022.

In an embodiment, the power traces 1031 may be coupled to the top andbottom surfaces of the core by vias 1032. Similarly, vias 1042 maycouple the signal traces 1041 to the top surface and the bottom surfaceof the core 1020. The signal traces 1041 _(A) and 1041 _(B) may each becoupled to the top surface of the core 1020 and the bottom surface ofthe core 1020. Such a configuration allows for connections to be madebetween an overlying die (not shown) and a board below the core 1020.

Referring now to FIG. 10B, a cross-sectional illustration of amulti-layer core 1020 is shown, in accordance with an additionalembodiment. In an embodiment, the routing for the signal traces 1041_(A) and 1041 _(B) includes routing between two die side components.That is, the vias 1042 only extend up to the topside of the core 1020.Such an embodiment allows for a die to be coupled to an adjacent dieside component, such as a connector, an optical module, a die, achiplet, or the like. In some embodiments, trace 1041 a mayalternatively be coupled from the top side (i.e., die side) to thebottom side (i.e., board side) by using a via 1042 that passes throughthe glass layer 1010 _(A). In yet another embodiment, trace 1041 a mayconnect the die to the die side components, and the trace 1041 _(B) mayconnect the die side to the board side.

FIG. 10B also includes power traces 1031 that have a thickness that isgreater than the thickness of the signal traces 1041. For example, thepower trace 1031 _(A) extends into the first glass layer 1010 _(A). Forexample, a cavity 1038 may be formed in the first glass layer 1010 _(A)to accommodate the thicker trace 1031 _(A). Similarly, the top trace1031 _(B) may extend into a cavity 1038 formed into the second glasslayer 1010 _(B). Portions of the traces 1031 _(A) and 1031 _(B) may alsoextend further into the interface layer 1022 than the distance thetraces 1041 _(A) and 1041 _(B) extend into the interface layer 1022. Inyet another embodiment, the trace 1031 _(A) and the trace 1031 _(B) maymerge together to form a single trace through the thickness of theinterface layer 1022. Additionally, while referred to as traces, it isto be appreciated that traces 1031 _(A) and 1031 _(B) may optionally beplanes.

Referring now to FIG. 10C, a cross-sectional illustration of amulti-layer core 1020 is shown, in accordance with an additionalembodiment. In an embodiment, the core 1020 comprises a first glasslayer 1010 _(A) and a second glass layer 1010 _(B). The first glasslayer 1010 _(A) may be coupled to the second glass layer 1010 _(B) by aninterface layer 1022, such as a buildup film. In an embodiment, signaltraces 1041 _(A) and 1041 _(B) may be embedded in the interface layer1022. For example, traces 1041 _(A) may be provided at the bottom of theinterface layer 1022. The traces 1041 a may include sidewall surfacesand a top surface that is directly contacted by the interface layer1022. A bottom surface of the traces 1041 a may be directly contacted bythe first glass layer 1010 _(A). The traces 1041 _(B) may be provided atthe top of the interface layer 1022. The traces 1041 _(B) may includesidewall surfaces and a bottom surface that is directly contacted by theinterface layer 1022. A top surface of the traces 1041 _(B) may bedirectly contacted by the second glass layer 1010 _(B). As shown, groundplanes 1011 may be provided over and under the core 1020. Ground vias1012 may pass through a thickness of the core 1020.

Referring now to FIG. 10D, a cross-sectional illustration of amulti-layer core 1020 is shown, in accordance with an additionalembodiment. As shown in FIG. 10D, a plurality of different routingarchitectures may be included within a single core 1020. For example,three different routing architectures 1071, 1072, and 1073 are shown inFIG. 10D. The first routing architecture 1071 may be a low loss SerDestype routing architecture. In such an embodiment, traces 1043 may beseparated from a ground plane by the second glass layer 1010 _(B) on oneside and by the interface layer 1022 on the other side. The secondrouting architecture 1072 may be a high-density single ended signalingarchitecture. As shown, a plurality of traces 1044 may be adjacent toeach other and within the interface layer 1022. In an embodiment, thetraces 1044 are close to the ground plane 1011 at the top of theinterface layer 1022. In an embodiment, the third routing architecture1073 is an ultra-low loss signaling architecture (e.g., suitable forSerDes signaling). As shown, the traces 1041 are spaced away from thenearest ground plane 1011 by at least the thickness of the second glasslayer 1010 _(B). On the other side, the ground plane 1011 is spaced awayfrom the traces 1041 by the thickness of the first glass layer 1010 _(A)and the thickness of the interface layer 1022. Additionally, thedistance between the traces 1041 and 1044 may be modulated using blindcavities that are filled with metal, similar to embodiments described ingreater detail above.

Referring now to FIGS. 11A and 11B, cross-sectional illustrations of amulti-layer core 1120 with cavities to reduce the distance between thetraces and the ground plane are shown, in accordance with an embodiment.By controlling the depth of the cavity, different types of routingarchitectures can be enabled within a single core 1120.

Referring now to FIG. 11A, a cross-sectional illustration of amulti-layer core 1120 is shown, in accordance with an embodiment. In anembodiment, the core 1120 comprises a first glass layer 1110 _(A) and asecond glass layer 1110 _(B). An interface layer 1122 is providedbetween the glass layers 1010 _(A) and 1010 _(B). In an embodiment,traces 1141 and traces 1144 may be provided in the interface layer 1122.As shown, a first cavity 1181 is provided in the second glass layer 1110_(B) over the traces 1141, and a second cavity 1182 is provided in thefirst glass layer 1110 _(A) below the traces 1144. In an embodiment, thedepth of the second cavity 1182 is greater than a depth of the firstcavity 1181. It is to be appreciated that the metal between the secondglass layer 1110 _(B) and interface layer 1122, between the first glasslayer 1110 _(A) and the interface layer 1122, and vias through theinterface layer 1122 are omitted in order to simplify the Figure.

Referring now to FIG. 11B, a cross-sectional illustration of the core1120 in FIG. 11A after the ground planes 1111 are formed is shown, inaccordance with an embodiment. In an embodiment, the ground planes 1111may be coupled to conductive blocks 1183 and 1184. The conductive blocks1183 and 1184 fill the cavities 1181 and 1182. Since they areelectrically coupled to the ground planes 1111, the conductive blocks1183 and 1184 can decrease the distance between the traces 1141 and 1144and the ground In an embodiment, the distance between the traces 1144and the ground is smaller than the distance between the traces 1141 andthe ground Furthermore, it is to be appreciated that the metal of theconductive blocks 1183 and 1184 would typically be deposited withdifferent deposition processes than the processes used to form the vias1112 through the interface layer 1122, and the metal between the glasslayers 1110 _(A-B) and the interface layer 1122.

Referring now to FIG. 12A, a cross-sectional illustration of amulti-layer core 1220 is shown, in accordance with an additionalembodiment. Particularly, the multi-layer core 1220 includes a pluralityof glass layers 1210 _(A) to 1210 _(N). Metal layers 1217 may be betweenthe glass layers 1210. Such an embodiment illustrates that there neednot be any particular number of glass layers 1210 _(A) to 1210 _(N). Thenumber of glass layers may be dependent on the routing needs of a givenpackage architecture. In an embodiment, any of the routing architecturesdescribed herein can be modified to be used with a multi-layer core 1220with a plurality of glass layers 1210. In an embodiment, adhesiveinterface layers (not shown) may also be provided between the glasscores 1210 to fill gaps in the metal layers 1217.

Referring now to FIG. 12B, a cross-sectional illustration of amulti-layer core 1220 is shown, in accordance with an additionalembodiment. Similar to the embodiment shown in FIG. 12A, there may beany number of glass layers 1210 _(A) to 1210 _(N) with metal layers 1217therebetween. However, the embodiment in FIG. 12B may also includeinterface layers 1222 between each of the glass layers 1210. Theinterface layers 1222 may comprise a buildup film or other adhesivematerial. In an embodiment, any of the routing architectures describedherein can be modified to be used with a multi-layer core 1220 with aplurality of glass layers 1210. Additionally, it is to be appreciatedthat the embodiment shown in FIG. 12B may be used in conjunction withthe embodiment shown in FIG. 12A to provide a hybrid core.

Referring now to FIG. 13 , a cross-sectional illustration of anelectronic system 1300 is shown, in accordance with an embodiment. In anembodiment, the electronic system 1300 may comprise a board 1391, suchas a printed circuit board (PCB) or the like. A package substrate may becoupled to the board 1391 by interconnects 1392. While shown as solderballs, it is to be appreciated that interconnects 1392 may be anyinterconnect architecture, such as sockets or the like.

In an embodiment, the package substrate comprises a multi-layer core1320 and buildup layers 1385 above and below the core 1320. The core1320 may comprise a first glass layer 1310 _(A) and a second glass layer1310 _(B). The first glass layer 1310 _(A) may be coupled to the secondglass layer 1310 _(B) by an interface layer 1322. A trace 1341 may beprovided in the interface layer 1322. Vias 1342 may couple the trace1341 to routing in the buildup layers 1385 above and below the core1320. For example, routing in the top buildup layers 1385 may couple thetrace 1341 to a die 1395, and routing in the bottom buildup layers 1385may couple the trace 1341 to the board 1391. In an embodiment, the die1395 is coupled to the package substrate by interconnects 1396. Theinterconnects 1396 may be any suitable first level interconnectarchitecture. In the particular embodiment shown in FIG. 13 , the core1320 includes a pair of glass layers. However, it is to be appreciatedthat any multi-layer core architecture disclosed herein may be used inthe electronic system 1300.

FIG. 14 illustrates a computing device 1400 in accordance with oneimplementation of the invention. The computing device 1400 houses aboard 1402. The board 1402 may include a number of components, includingbut not limited to a processor 1404 and at least one communication chip1406. The processor 1404 is physically and electrically coupled to theboard 1402. In some implementations the at least one communication chip1406 is also physically and electrically coupled to the board 1402. Infurther implementations, the communication chip 1406 is part of theprocessor 1404.

These other components include, but are not limited to, volatile memory(e.g., DRAM), non-volatile memory (e.g., ROM), flash memory, a graphicsprocessor, a digital signal processor, a crypto processor, a chipset, anantenna, a display, a touchscreen display, a touchscreen controller, abattery, an audio codec, a video codec, a power amplifier, a globalpositioning system (GPS) device, a compass, an accelerometer, agyroscope, a speaker, a camera, and a mass storage device (such as harddisk drive, compact disk (CD), digital versatile disk (DVD), and soforth).

The communication chip 1406 enables wireless communications for thetransfer of data to and from the computing device 1400. The term“wireless” and its derivatives may be used to describe circuits,devices, systems, methods, techniques, communications channels, etc.,that may communicate data through the use of modulated electromagneticradiation through a non-solid medium. The term does not imply that theassociated devices do not contain any wires, although in someembodiments they might not. The communication chip 1406 may implementany of a number of wireless standards or protocols, including but notlimited to Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE802.20, long term evolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE,GSM, GPRS, CDMA, TDMA, DECT, Bluetooth, derivatives thereof, as well asany other wireless protocols that are designated as 3G, 4G, 5G, andbeyond. The computing device 1400 may include a plurality ofcommunication chips 1406. For instance, a first communication chip 1406may be dedicated to shorter range wireless communications such as Wi-Fiand Bluetooth and a second communication chip 1406 may be dedicated tolonger range wireless communications such as GPS, EDGE, GPRS, CDMA,WiMAX, LTE, Ev-DO, and others.

The processor 1404 of the computing device 1400 includes an integratedcircuit die packaged within the processor 1404. In some implementationsof the invention, the integrated circuit die of the processor may bepart of an electronic package that comprises a multi-layer core withsignal and/or power routing in an interface layer between glass layers,in accordance with embodiments described herein. The term “processor”may refer to any device or portion of a device that processes electronicdata from registers and/or memory to transform that electronic data intoother electronic data that may be stored in registers and/or memory.

The communication chip 1406 also includes an integrated circuit diepackaged within the communication chip 1406. In accordance with anotherimplementation of the invention, the integrated circuit die of thecommunication chip may be part of an electronic package that comprises amulti-layer core with signal and/or power routing in an interface layerbetween glass layers, in accordance with embodiments described herein.

The above description of illustrated implementations of the invention,including what is described in the Abstract, is not intended to beexhaustive or to limit the invention to the precise forms disclosed.While specific implementations of, and examples for, the invention aredescribed herein for illustrative purposes, various equivalentmodifications are possible within the scope of the invention, as thoseskilled in the relevant art will recognize.

These modifications may be made to the invention in light of the abovedetailed description. The terms used in the following claims should notbe construed to limit the invention to the specific implementationsdisclosed in the specification and the claims. Rather, the scope of theinvention is to be determined entirely by the following claims, whichare to be construed in accordance with established doctrines of claiminterpretation.

Example 1: a package core, comprising: a first layer, wherein the firstlayer comprises glass; a second layer over the first layer, wherein thesecond layer comprises glass; a third layer over the second layer,wherein the third layer comprises glass; a first trace between the firstlayer and the second layer; and a second trace between the second layerand the third layer.

Example 2: the package core of Example 1, wherein a first adhesivecouples the first layer to the second layer, and a second adhesivecouples the second layer to the third layer.

Example 3: the package core of Example 2, wherein the first trace has athickness that is substantially equal to a thickness of the firstadhesive, and wherein the second trace has a thickness that issubstantially equal to a thickness of the second adhesive.

Example 4: the package core of Examples 1-3, further comprising: firstvias that couple the first trace to a top surface and a bottom surfaceof the core; and second vias that couple the second trace to a topsurface and a bottom surface of the core.

Example 5: the package core of Examples 1-4, further comprising: a firstvia that couples a first end of the second trace to a top surface of thecore; and a second via that couples a second end of the second trace tothe top surface of the core.

Example 6: the package core of Example 5, further comprising: a thirdvia that couples a first end of the first trace to the top surface ofthe core; and a fourth via that couples a second end of the first traceto the top surface of the core.

Example 7: the package core of Example 5, further comprising: a thirdvia that couples a first end of the first trace to the top surface ofthe core; and a fourth via that couples a second end of the first traceto a bottom surface of the core.

Example 8: the package core of Examples 1-7, further comprising:cavities into the first layer and the second layer, wherein the firsttrace fills the cavities.

Example 9: the package core of Examples 1-8, further comprising: a firstconductive plane over a top surface of the core; and a second conductiveplane over a bottom surface of the core.

Example 10: the package core of Example 9, further comprising: a firstcavity into the top surface of the core, wherein the first cavity isfilled by the first conductive plane; and a second cavity into thebottom surface of the core, wherein the second cavity is filled by thesecond conductive plane.

Example 11: the package core of Examples 8-10, wherein the first traceand the second trace are part of dual stripline routing architectures.

Example 12: an electronic package, comprising: a multi-layer core,wherein a plurality of the layers in the multi-layer core compriseglass; a first routing architecture in the multi-layer core; and asecond routing architecture in the multi-layer core, wherein the secondrouting architecture is different than the first routing architecture.

Example 13: the electronic package of Example 12, wherein the firstrouting architecture is a low loss routing architecture.

Example 14: the electronic package of Example 12 or Example 13, whereinthe second routing architecture is a single-ended signaling routingarchitecture.

Example 15: the electronic package of Examples 12-14, further comprisinga third routing architecture in the multi-layer core, wherein the thirdrouting architecture is a high speed differential routing architecture.

Example 16: the electronic package of Examples 12-15, furthercomprising: adhesive layers between the plurality of layers.

Example 17: the electronic package of Example 16, wherein the firstrouting architecture and the second routing architecture are surroundedby the adhesive layers.

Example 18: the electronic package of Example 17, wherein the firstrouting architecture comprises traces that extend into cavities formedin the plurality of layers.

Example 19: the electronic package of Examples 12-18, wherein theplurality of layers comprises three or more layers.

Example 20: an electronic system, comprising: a board; a packagesubstrate coupled to the board, wherein the package substrate comprises:a first layer, wherein the first layer comprises glass; a second layerover the first layer, wherein the second layer comprises glass; a thirdlayer over the second layer, wherein the third layer comprises glass; afirst trace between the first layer and the second layer; and a secondtrace between the second layer and the third layer; and a die coupled tothe package substrate.

Example 21: the electronic system of Example 20, wherein a firstadhesive couples the first layer to the second layer, and a secondadhesive couples the second layer to the third layer.

Example 22: the electronic system of Example 21, wherein the first tracehas a thickness that is substantially equal to a thickness of the firstadhesive, and wherein the second trace has a thickness that issubstantially equal to a thickness of the second adhesive.

What is claimed is:
 1. A package core, comprising: a first layer,wherein the first layer comprises glass; a second layer over the firstlayer, wherein the second layer comprises glass; a third layer over thesecond layer, wherein the third layer comprises glass; a first tracebetween the first layer and the second layer; and a second trace betweenthe second layer and the third layer.
 2. The package core of claim 1,wherein a first adhesive couples the first layer to the second layer,and a second adhesive couples the second layer to the third layer. 3.The package core of claim 2, wherein the first trace has a thicknessthat is substantially equal to a thickness of the first adhesive, andwherein the second trace has a thickness that is substantially equal toa thickness of the second adhesive.
 4. The package core of claim 1,further comprising: first vias that couple the first trace to a topsurface and a bottom surface of the core; and second vias that couplethe second trace to a top surface and a bottom surface of the core. 5.The package core of claim 1, further comprising: a first via thatcouples a first end of the second trace to a top surface of the core;and a second via that couples a second end of the second trace to thetop surface of the core.
 6. The package core of claim 5, furthercomprising: a third via that couples a first end of the first trace tothe top surface of the core; and a fourth via that couples a second endof the first trace to the top surface of the core.
 7. The package coreof claim 5, further comprising: a third via that couples a first end ofthe first trace to the top surface of the core; and a fourth via thatcouples a second end of the first trace to a bottom surface of the core.8. The package core of claim 1, further comprising: cavities into thefirst layer and the second layer, wherein the first trace fills thecavities.
 9. The package core of claim 1, further comprising: a firstconductive plane over a top surface of the core; and a second conductiveplane over a bottom surface of the core.
 10. The package core of claim9, further comprising: a first cavity into the top surface of the core,wherein the first cavity is filled by the first conductive plane; and asecond cavity into the bottom surface of the core, wherein the secondcavity is filled by the second conductive plane.
 11. The package core ofclaim 8, wherein the first trace and the second trace are part of dualstripline routing architectures.
 12. An electronic package, comprising:a multi-layer core, wherein a plurality of the layers in the multi-layercore comprise glass; a first routing architecture in the multi-layercore; and a second routing architecture in the multi-layer core, whereinthe second routing architecture is different than the first routingarchitecture.
 13. The electronic package of claim 12, wherein the firstrouting architecture is a low loss routing architecture.
 14. Theelectronic package of claim 12, wherein the second routing architectureis a single-ended signaling routing architecture.
 15. The electronicpackage of claim 12, further comprising a third routing architecture inthe multi-layer core, wherein the third routing architecture is a highspeed differential routing architecture.
 16. The electronic package ofclaim 12, further comprising: adhesive layers between the plurality oflayers.
 17. The electronic package of claim 16, wherein the firstrouting architecture and the second routing architecture are surroundedby the adhesive layers.
 18. The electronic package of claim 17, whereinthe first routing architecture comprises traces that extend intocavities formed in the plurality of layers.
 19. The electronic packageof claim 12, wherein the plurality of layers comprises three or morelayers.
 20. An electronic system, comprising: a board; a packagesubstrate coupled to the board, wherein the package substrate comprises:a first layer, wherein the first layer comprises glass; a second layerover the first layer, wherein the second layer comprises glass; a thirdlayer over the second layer, wherein the third layer comprises glass; afirst trace between the first layer and the second layer; and a secondtrace between the second layer and the third layer; and a die coupled tothe package substrate.
 21. The electronic system of claim 20, wherein afirst adhesive couples the first layer to the second layer, and a secondadhesive couples the second layer to the third layer.
 22. The electronicsystem of claim 21, wherein the first trace has a thickness that issubstantially equal to a thickness of the first adhesive, and whereinthe second trace has a thickness that is substantially equal to athickness of the second adhesive.